original researcharticle doi: 10.26479/2019.0502.35 ...accumulation of trace metals happens in...

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Original ResearchArticle DOI: 10.26479/2019.0502.35

ECOTOXICOLOGICAL IMPACT ASSESSMENT OF HEAVY METALS IN

CORE SEDIMENTS OF KATTAMPALLY - A WETLAND IN THE

SOUTHWEST COAST OF INDIA

P. S. Harikumar*, P. V. Jiji

Center for Water Resources Development and Management, Kunnamangalam,

Kozhikode, Kerala, India.

ABSTRACT: Vertical distribution of heavy metal concentration in four cores from Kattampally

wetland system was studied. Concentration of iron, manganese, nickel, zinc, cadmium, lead and

copper in each slices of sediment was determined. Degree of contamination for each station was

determined. Qualities of the sediments were evaluated based on sediment quality guidelines,

pollution load index and sum of toxic units. The results of the study revealed the concentration of

heavy metals in the core sediment variesconsiderably across depths. Higher concentration of trace

metals in surface layers than in deeper ones. Core sediments in Kattampally were polluted in heavy

rate for nickel and moderate rate for zinc, according to effects based sediment quality guidelines.

The potential acute toxicity of nickel in some stations exceeded the effect range median levels,

which represents a probable effect range within which adverse biological effects frequently occur.

Statistical analysis showed that the correlation among completely different parameters differs

with reference to stations. The present study confirmed that the Kattampally wetland is under

considerable contamination due to heavy metals.

KEYWORDS: Core sediments, Heavy metals, Vertical distribution, Sediment quality guidelines.

Corresponding Author: Dr. P. S. Harikumar* Ph.D.

Center for Water Resources Development and Management, Kunnamangalam,

Kozhikode, Kerala, India.

1.INTRODUCTION

Sediments will be sensitive indicators for observation contaminants in aquatic environments.

The favourable physico-chemical conditions of the sediment will remobilize and unharness the

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metals to the water column. Core sediments give helpful data on the changes within the quality

of the lake from a past amount. Several researchers had studied the pollution history of

aquatic system by core sediments [12]; [16]; [20]. Sediment cores were accustomed study the

behavior of metals [9]. Sediment core contain data concerning the events that occurred in

precultural time within the lakes and its catchments space. The sediment history broadly

speaking reflects the contamination history of a region. Currently, environmental

pollution owing to urbanization and industrial development may be a major concern [11];

[28].Sediment quality analysis of a water body is one in all the necessary aspects of

evaluating the whole health standing of land ecosystems because it reflects long quality condi

tion [21].The high concentrations of serious metals square measure derived from anthropogen

etic inputs from industrial activities round the body of water [30].; [3]. Concentration of trace

metals in coastal estuaries will be elevated thanks to high inputs from natural likewise as anth

ropogenetic sources. Therefore understanding the transport and distribution of trace metals in

estuaries may be a goal of environmental chemists [35].Kattampally is a coastal wetland in the

North Malabar region of Kerala.Extensive wetland areas lying fallow and abandoned on either side

of the Kattampally River, a tributary of the Valapattanam River. The ecologically sensitive

Kattampally wetland system was once noted for Kaipad cultivation. There is no study available

about the status of core sediments of this wetland on heavy metal contamination status. Thus, this

study was carried out to understand the vertical distribution of heavy metals in wetland core

sediments that will give some insight in to the pollution status of the Kattampally and to identify

possible sources.

2. MATERIALS AND METHODS

The core samples of sediments were collected using the Kajak gravity corer of 1m length. The

sampling stations include Munderikadavu (K1), Pulluppi (K2), Mathodam (K3) and Varamkadavu

(K4). A total of four sediment cores were collected, cut into slices ofapproximately 2-4 cm length

and properly labelled. The details of the samplingstations are indicated in Fig. 1. The samples (each

slices of the core) were delivered to the laboratory victimisation ice baggage and keep in a

verydeep freeze unit till the drying procedure [34].For the digestion of the sediment sample one

gram of dried and homogenized sediment samples were weighed and placed into an acid washed

PTFE digestion vessel. The digestion was performed with a mixture HNO3 and HClO4.The digested

samples were analyzed for heavy metals with atomic absorption spectrometer [36]. The

concentration of iron, manganese, cadmium, copper, lead, nickel and zinc were determined in each

slices of the core sediment and the values are reported in units of mg/kg except iron and manganese

which is in g/kg.The need for chemical pointers that would be wont to predict adverse

biological effects in contaminated sediments cause the event of sediment quality pointers [15]

;[17];[19]. Numerical sediment quality pointers (SQGs) are wont to establish contaminants of






concern in aquatic system[17].The National Oceanic and region Administration (NOAA) de

veloped a collection of empirical SQGs [14] that has 2 values, effects vary low (ERL) and eff

ects vary median(ERM), that delineate 3 concentration ranges for every explicit chemical and

therefore the corresponding estimation of the potential biological impact. The concentrations

below ERL represent a minimal- effects vary, that is meant to estimate conditions wherever bi

ological effects are seldom determined. Concentrations adequate to or bigger than ERL, howe

ver but ERM represents a spread with during which biological effects occur sometimes.

Concentrations at or on top of ERM values represents a probable impact vary with, during

which adverse biological effects of times occur. Sediments also are accustomed rank

and/or grade contaminated areas or chemicals of concern for additional investigation

or accustomed value spacial pattern of sediment contamination[2]; [6]. Sediments were classif

ied as: nonpolluted, moderately impure and heavily impure, supported SQG of EPA [24].The t

actic recommended by Hakanson et al. (1980), to search out out the contamination issue (Cf)

and therefore the degree of contamination (Cd), that describe the contamination of

given harmfulsubstance has been employed in this study. The potential acute harmfulity of

contaminants in sediment sample iscalculable because the total of the toxic units

(PTU) outlined because the magnitude relation of the determined concentration

to pixel price [23]. Tomlinson et al. (1980) had utilized an easy methodology

supported pollution load index (PLI) to assess extend of pollution by metals in body of

water sediments. The PLI price of o1 indicate no pollution, were as forty one indicates

pollution of the aquatic system. The extend of pollution increase with increase within

the numerical rate.

Fig. 1.Area map of Kattampallywetland showing sampling sites

3. RESULTS AND DISCUSSION

3.1. Variation of heavy metal along the core

Vertical distribution of heavy metals concentrations in the present study revealed that, iron (Fe)

showed the highest concentration compared to other heavy metals in all samples. The concentration

of iron varied from 14.24 g/kg to 102.71g/kg (fig 2a). The highest distribution was found at the






station K4 which is an agricultural area. The distribution pattern is almost uniform along the core

with small increasing trend at stations k2,k3 and k4. Spatial variation of average concentration of

iron was in the order K4> K2> K3> K1. The concentration of manganese (Mn) varied from 0.03g/kg

to 1.11g/kg.(fig 2b) The average manganese concentrations is in the order K2> K3> K4> K1 with a

slight increase in concentration towards the top layers except K3. Nickel was present at high

concentrations in marine core sediment. The concentration of Ni ranged between 32.5 mg/kg to 120

mg/kg. Vertical distribution of Ni is not consistent from the surface layer towards the lower layer of

sediment. (fig 2c). The average nickel content of K1, K2, K3 and K4 were 48.5,82, 85 and 93mg/kg.

An EPA criterion for heavily polluted sediments for Ni is >50 mg/kg and K2, K3 and K4 exceeds

the limits. The concentration of zinc varied from 22.50 to 102.50mg/kg. The pollution due to zinc

in the sediments is moderately polluted as it compared with the USEPA sediment quality guidelines

(1999).Concentration of copper was found to be below detection limit in K1 and K2. But the

pollution of the Wetland with respect to copper is very high and exceeds the EPA criteria for heavily

polluted sediments of >50 mg/kg in K3 and K4. A maximum concentration of copper (75 mg/kg)

was found in the bottom layer of the sediment cores. The down core variation of copper follows a

increasing trend. The concentration of lead and cadmium were found to be below detection limit in

all the core samples collected from Kattampally wetland system. The spatial and temporal variations

are given in Fig.2a to 2d.

Fig. 2. (a), (b), (c), (d) Down core variation of iron, manganese, nickel and zinc in

Kattampally wetland

0

20000

40000

60000

80000

100000

120000

0-20 21-3031-4041-5051-60

Fe,m

g/k

g

Depth , cm

K1

K2

K3

K4 0

200

400

600

800

1000

1200

0-20 21-3031-4041-5051-60

Mn

, m

g/k

g

Depth , cm

K1

K2

K3

K4

0

20

40

60

80

100

120

140

0-20 21-30 31-40 41-50 51-60

Ni,

mg/k

g

Depth , cm

K1

K2

K3

K4

0

20

40

60

80

100

120

0-20 21-30 31-40 41-50 51-60

Zn

,mg/k

g

Depth , cm

K1

K2

K3

K4






DISCUSSION

4.1. Statistical analysis

Accumulation of trace metals happens in higher sediment in aquatic setting by biological and

geochemical mechanisms and becomes noxious to sediment-dwelling organisms and

fish, leading to death, reduced growth, or in impaired replica and lower species diversity [22].

The variation in weathering, erosion, transport conditions, and aquatic productivity, the

accumulated sediments have totally different characters in grain size, mineral, organic matters

content, etc., which might additionally produce anomalously high serious metals

concentration moreover as anthropogenic contamination [13].The concentration and

distribution of serious metals within the aquatic systems ar influenced by sorption and co-

precipitation with iron and atomic number 25 oxides [10].so as to quantitatively analyze and

make sure the connection among sediment parameter (organic matter) and serious metal

content, a Pearson’s correlation analysis was applied to the dataset and also the results were

tabulated in Table 1.The present study revealed that the correlation among different parameters

differs with respect to stations. In the station K1, the organic matter showed good positive correlation

with all the heavy metals. But for K2 manganese, nickel and zinc showed negative correlation with

organic matter whereas iron showed positive correlation with organic matter. In the station K3, iron

only showed negative correlation with organic matter and in k4 the organic matter showed positive

correlation with all the heavy metals. The metals iron and manganese showed positive correlation

with other metals in core collected from stations K1 and K3. But in K2 Manganese showed a positive

correlation with nickel and zinc.

Table 1: Pearson’s correlation among organic matter and the heavy metal content in each

slice of the sediment cores

Average organic matter for station K1= 17.6%

K1 om Fe Mn Ni Zn

om 1

Fe 0.824938 1

Mn 0.91394 0.871186 1

Ni 0.764957 0.93688 0.932871 1

Zn 0.882221 0.963808 0.968723 0.976269 1


K2 om Fe Mn Ni Zn

om 1

Fe 0.688487 1






Mn -0.70689 -0.65595 1

Ni -0.67672 -0.72496 0.575789 1

Zn -0.82856 -0.60129 0.605638 0.935304 1


K3 om Fe Mn Ni Zn

om 1

Fe -0.24313 1

Mn 0.538277 0.652493 1

Ni 0.526149 0.507409 0.917859 1

Zn 0.212602 0.822892 0.892318 0.893443 1


K4 om Fe Mn Ni Zn

om 1

Fe 0.172971 1

Mn 0.109075 -0.09307 1

Ni 0.642425 -0.47726 0.077772 1

Zn 0.938742 0.1553 0.439419 0.561421 1

O.M- Organic Matter.

4.2. Assessment of sediment pollution using different indices sediment contamination by

comparison with effect based sediment quality guidelines

Average concentration of serious metals in sediments at totally different|completely different}

depths and their comparative assessment with different international sediment quality tips (SQGs)

prompt by Perin et al. [24].square measure tabulated in Table a pair of. altogether the stations except

K1, concentration of nickel was higher than fifty mg/kg, that belongs to the category of heavily

contaminated sediments in line with SQG and USEPA. The concentration of Zn was 90mg/kg in K4

that belongs to the category of moderately contaminated sediments in line with SQG. The

concentration of Mn and metal was found in an exceedingly vary between low result level in line

with Ontario MOE. The concentration of Ni was underneath heavily contaminated and metal was

underneath moderately pollution classes. iron and Mn were the 2 metals having the next contribution

in sediments of the study website compared to different metals (Table 2). The concentration of iron

was nearly thrice on top of the low result level of Ontario MOE whereas Mn was below it. The

sources for iron and Mn square measure weathering and soil erosions [31]. Iron and Mn square






measure vital parts for metabolic reactions in plants and animals. but in excess concentrations, they

typically disrupt metabolism, circulation and nerve sensations in animals [29]. Ni was ascertained

quite 5 times on top of the low result level of Ontario MOE in sediments of this study. Major sources

of Ni and metal square measure domestic wastewaters, waste matter effluents, agricultural runoff,

and fuel burning, steel and metal alloys [25]; [26]; 7]; [27]. These metals effect serious human health

consequences in skin, lungs and nervous systems [4].

Table 2: Concentration of heavy metals in the sediment core and its comparison with

different SQGs.

SQGs OntarioMOEa USEPA

Element

mg/kg

Sampling stations SQG

NP

SQG

MP

SQG

HP

LEL SEL NP MP HP

K1 K2 K3 K4 Fe 20,000 40,000 - - -

Mn 110 388 145.2 129.5 - - - Mn 460 1100 - - -

Ni 48.5 82 85 93 ˂20 20-50 ˃50 Ni 16 75 <20 20-50 >50

Zn 44 83 82.5 90 ˂90 90-200 ˃200 Zn 120 820 <90 90-200 <200

4.3. Assessment of sediment contamination by comparison of concentration with those of

background sediments

The contamination factor and degree of contamination for the core sediment samples at each station

were calculated using modified equation of Hakanson et al. [8] proposed by Abrahim and Parker

(2008) (Table 3).Taylor’s (1972) crustal abundance was used as the reference baselines. The

following terminologies are used to describe the degree of contamination (mCd).

mCd ≤ 1.5 Nil to very low degree of contamination

1.5 ≤ mCd ˂ 2 Low degree of contamination

2 ≤ mCd ˂ 4 Moderate degree of contamination

4 ≤ mCd ˂ 8 High degree of contamination

8 ≤ mCd ˂ 16 Very high degree of contamination

16 ≤ mCd ˂ 32 Extremely high degree of contamination

mCd ≥ 32 Ultra high degree of contamination

From the results it was found that the contamination factor values were found in a range of 0.30-

2.20 for Fe, 0.03-1.23 for Mn, for 0.48-1.76 Ni and 0.24-1.84 for Zn. All metals were observed in

two classes namely low contamination (LC) and moderate contamination (MC) (Table 3). Fe and

Ni were found in moderate contamination throughout the depths except in sampling station K1. On

the basis of average CF values the metals were found in the sequence of Fe >Ni >Zn>Mn. But the

degree of contamination calculated for the stations K1,K2, K3 and K4 were 0.46, 0.98,0.84 and 1.02,

respectively, which are very low. This indicates low degree of heavy metal contamination






Table 3: Contamination factor and degree of contamination of the wetland core sediments

Cf

Element K1 K2 K3 K4

Fe 0.56 1.42 1.08 1.62

Mn 0.12 0.43 0.16 0.14

Ni 0.71 1.21 1.25 1.37

Zn 0.46 0.87 0.87 0.95

mCd 0.46 0.98 0.84 1.02

4.4. Assessment of pollution by computing the pollution load index (PLI)

Pollution load index proposed by Tomlinson et al. (1980), has been used in the present study to

determine the mutual pollution effect at different stations by different elements ([18]. The PLI values

for each of the stations were calculated. The average concentration and the concentration present at

the surface of the sediment core were compared with the average concentration of world shale

[33].The trace element concentration along with the calculated PLI values was given in Table 4.

Table 4:Comparison of heavy metal in each core with average shale value and the numerical

value of PLI calculated using the method of Tomlinson et al. (1980).

The calculated values of pollution load index of sediment samples were observed in two classes

value between 0.5 and 1, which suggest more detailed study to monitor the site and value greater

than 1 Indicates an immediate intervention to reduce pollution. PLI values greater than 1 was

reported in K2.

4.5 Ecotoxicological sense of heavy metal contamination

The sediment quality guidelines developed by Bakan and Ozkoc for marine and estuarial system

[1]were utilized in the current study to see the ecotoxicological sense of serious metal

contamination within the core sediments of poultry body of water. Chemical concentrations

Element/

Stations K1 K2 K3 K4

Average

Shale

Concentration of metal in different parts of the core sediment

Average

Surface

(top layer) Average

Surface

(top layer) Average

Surface

(top layer) Average

Surface

(top layer)

Fe, g/kg 25.93 34.55 66.48 61.55 50.27 42.57 75.83 63.97 45.7

Mn, g/kg 0.11 0.17 0.39 1.11 0.15 0.03 0.13 0.19 0.85

Ni,mg/kg 48.50 57.50 82.00 92.50 85.00 65.00 93.00 90.00 68

Zn,mg/kg 44.00 62.50 83.00 92.50 82.50 65.00 90.00 92.50 95

PLI 0.38 0.52 0.83 1.2 0.71 0.45 0.81 0.82






comparable to the tenth and fiftieth percentiles of adverse biological effects were referred to as

the results range-low (ERL) and effects-range median (ERM) pointers, severally [15].

Considering the results, the serious metal concentration of nickel at station K1 and metallic

element in any respect stations were below ERL that represent a minimal-effects vary, that is

meant to estimate conditions wherever biological effects area unit seldom ascertained. For

stations Godwin Austen, K3 and K4 concentration of nickel exceeded the ERM levels, that

represents a probable impact vary with during which adverse biological effects often occur. The

potential acute harmfulity of contaminants in sediment sample was calculable (Table 5) because

the total of the toxic units (PTU) outlined because the magnitude relation of the determined

concentration to constituent price [23].The harmful unit values at stations K1, K2, K3 and K4

area unit one.29, 2.21, 2.28 and 2.50 respectively.

Table 5: Sum of toxic units (TU) of core sediments and various guidelines for heavy metals.

Element Stations TEL PEL ERL ERM

K1 K2 K3 K4

Ni ,mg/kg 48.5 82.00 85.00 93.00 15.90 43.00 20.90 51.60

Zn, mg/kg 44 83.00 82.50 90.00 124.00 270.00 150.00 410.00

ΣTU 1.29 2.21 2.28 2.50

4. CONCLUSION

The study of ecotoxicological impact assessment of trace metals in core sediments of Kattampally

wetland demonstrates that the estuary is facing severe heavy metal pollution. The concentration of

heavy metals in the sedimentofKattampally wetland variesconsiderably across depths. The present

study reported higher concentration of trace metals in surface layers than in deeper ones due to

development of industries and other man-made activities. Down-core differences of elements

indicate an increase of trace elements probably during the past few periods. The Kattampally

wetland receives many pollutants from the nearby sources such as agriculture run-off, domestic

sewage, effluent from a plywood industries at present. The average concentration of heavy metals

in various stations of was found in a sequence of Fe> Mn > Ni > Zn > Cu > Pb>Cd. The present

study revealed that the correlation among different parameters differs with respect to stations. The

organic matter showed good positive Correlation with iron in all stations. Core sediments in

Kattampally were polluted in heavy rate for nickel and moderate rate for zinc according to effects

based sediment quality guidelines. Moderate degree of contamination of iron and nickel were found

throughout the depth. The potential acute toxicity of nickel exceeded the ERM levels, which

represents a probable effect range within which adverse biological effects frequently occur. The

spatial variation in contamination due to different heavy metals is due the difference in the location

of industrial units. Anthropogenic source from the industrial activities at the upstream is the main

reasons contributing heavy load of trace metals to the Kattampally wetland and major sources of Ni






and Zn are domestic wastewaters, sewage effluents and agricultural runoff. The above results

confirmed that the Kattampally wetland is under considerable contamination due to heavy metals.

Although no research work was done before on the heavy metals in sediments of this important

Wetland, this study forms baseline information on heavy metal contamination in the wetland, which

can be used for further research. This data can also be helpful for policy makers in making

management plan of this wetland.

ACKNOWLEDGEMENT

The authors wish to express their gratitude to the Kerala State Science, Technology and Environment

(KSCSTE), Government of Kerala for the financial assistance to carryout the research work.

CONFLICT OF INTEREST

No conflict of interest exists.

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